Removal of flash, fin, and burr



April 1, 1952 H. N. MAIER REMOVALOF FLASH, FIN, Amp BURR Filed March 4,1947 FIG 2 38 TO SUPER SONIC AC SOURCE FIG I TO SONIC AC SOURCE FIG 3POWER SOURCE INVENTOR HERBERT N. MAI

BY Z

ATTORNEY Patented Apr. 1, 1952 REMOVAL OF FLASH, FIN, AND BURR HerbertN. Meier, Pottstown, Pa., assignor to Doehler-Jarvis Corporation, NewYork, N. Y., a

corporation of Michigan Application March 4, 1947, Serial No. 732,311

Claims.

This invention relates to the finishing of shaped bodies, and moreparticularly to the removal of flash, fin, safety edge, or/and burrtherefrom.

Flash or fin is left on a metal casting at the parting face of the mold,and at the ends of the ejector pins, particularly as the mold begins toWear. Even after the hash or fin is removed, a feather edge or burr mayremain. In die-casting practice, a so-called safety edge or overflow issometimes purposely provided to protect a corner edge of the casting, orto facilitate subsequent breaking-off of the overflow. Here again thesafety edge must be removed, and even then a burr is usually left afterremoval of the safety edge. Burr is not limited, however, to castings,and instead may be found on metal parts which have been subjected tostamping, coining, or forging operations, and machining operations suchas drilling and tapping. Moreover, the problem is not limited to metalobjects, for fiash or fin is produced when molding plastics.

Heretofore, various methods have been employed to remove flash, fin, orsafety edge. Sometimes a trimming die is employed. For very heavy flasha band-saw may be used. For a small, light flash, tumbling has beenemployed. Hand operations are often resorted to, including the use of amallet, a bending fixture, and files. For the removal of burrs, it hasbeen the practice to employ hand-filing, grinding wheels, de-burringWheels, belt sanders, and tumbling. All of the methods heretofore usedhave required considerable time and labor.

The primary object of the present invention is to provide a new, rapid,and relatively inexpensive method for removing iin, safety edge, andburr. In accordance with the new method, the objects are immersed in aliquid, and the liquid is vibrated at a relatively high frequency,preferably a sonic frequency, although a super sonic frequency may alsobe used.

To accomplish the foregoing general object, and other more specificobjects which will hereinafter appear, my invention resides in the meth0d and apparatus elements and their relation one to the other, as arehereinafter more particularly described in the following specification.The specification is accompanied by a drawing in which:

Fig. 1 schematically illustrates a form of the invention using amagnetic diaphragm;

Fig. 2 schematically illustrates a modification using a magnetostrictioneifect;

Fig. 3 shows a modification in which two diaphragms are vibrated inopposed phase; and

Fig. 4 is explanatory of a detail of the invention.

Referring to the drawing, and more particularly to Fig. 1, the apparatuscomprises a container 12 for a body of liquid M. The: container may bemade substantially higher than the liquid level, or in the alternative,a removable cover It may be employed, as shown. The apparatus furtherincludes means it to support a plurality of objects 23 in the liquid Hi.There is also a means 22 to vibrate the liquid it at a relatively highfrequency. In the present case, the liquid is vibrated at a sonicfrequency by a diaphragm which acts as the bottom wall of the container.The support I8 is a highly perforate basket. The diaphragm 22 isvibrated by means of an electromagnet 24, the said diaphragm forming apart of a magnetic circuit 25 having an air gap at 28. The magnet coilis connected to a suitable source of sonic frequency A. C. power.

A modification of the vibrator portion of the apparatus is schematicallyshown in Fig. 2. This differs from Fig. l primarily in using a metal rod30 fixedly connected between the housing 32 and the diaphragm 34. Thediaphragm is vibrated by magnetostrictive elongation and contraction ofthe rod 36 in response to an alternating magnetic field applied theretoby the coil 3%. The conductors 38 are connected to a sonic or asupersonic frequency source of power.

For the present purpose, multiple objects should be placed in mutualcontact in the liquid, for the flash, fin or burr is removed by theabrasion 01' rubbing of one object against the other. This is indicatedschematically in Fig. l, in which many objects 2!} are employed tolargely fill the basket or support it. When the objects are small, theymay be vibrated in direct contact with one another. When the articlesare large, or of some unusual shape, it may be preferred to supplementthem with additional objects which act fundamentally as fillers. This isschematically illustrated in Fig. 4, in which the cage or support 43contains a limited number of objects 42 the spaces between which arefilled with small auxiliary objects or fillers 44.

In effect, the water or other liquid in the tank acts merely as a meansto transfer the vibration from the diaphragm to the articles. For thispurpose, oil may be used instead of water, and in fact, in some respectsmay be better than Water, but in most manufacturing processes oil wouldhave the disadvantage of requiring a separate clegreasing operationwhich would. not be needed when using plain water.

The desired de-burring action may be ob- 3 tained by burying the objectsin a dry medium such' as fine sand. However, it is vastly moreconvenient to lower the objects into a body of liquid than to bury themin a dry mixture or sand, and the same applies to the subsequent removalof the objects.

With apparatus of the character here shown, de-burring was as effectivein one or two minutes as the older practice of tumbling would have beenin, say, a half-hour.

Referring now to Fig. 3, the container there shown carries a body ofliquid 52 in which objects 54 to be treated are supported by a suitableperforate or grid-like support 56. In this case the container isprovided with two spaced vibratile diaphragms 58 and 69, which contactthe liquid 52. The diaphragms are vibrated by suitable vibrator units 62and 64, respectively. These are energized from a power source 66, andare so wired to the source as to be vibrated in synchronism but in phaseopposition. Thus the diaphragm 58 will advance or push when diaphragm 60retracts or pulls. This efficiently sets the body of liquid intovibration. The diaphragms 58 and 60 may form a part of the wall of thecontainer, as here shown. It is sufficient that they be spaced wellapart, as for example, on the bottom wall, but it is preferable thatthey form parts of opposed walls of the container, as here shown.

Either a sonic or supersonic frequency of vibration may be employed. Ingeneral, it is simpler and easier to produce a sonic frequencyvibration, for it is not essential in that case to employ vacuum tubeoscillators and amplifiers, etc., although they may be used. On theother hand, a supersonic vibration has the advantage of avoiding theloud and disturbing noise produced by sonic equipment. Even in the caseof supersonic vibration, however, care must be taken not to employ afrequency which may adversely affect personnel working around theequipment.

It will be understood that the vibration of the diaphragm may beproduced in any of the known or conventional ways. The vibration of thediaphragm may be produced by mechanical means. The diaphragm may bevibrated by direct magnetic effect. It may also be vibrated by the useof a coil movably mounted in a suitable magnetic field, for example, aD. C. field, the coil carrying an excitation current, for example, apulsating or an A. C. current. This would be analogous to the operationof a so-called dynamic loud speaker. The diaphragm may also be vibratedby magnetotriction of a ferrous or nickle alloy or othermagnetostrictive rod, or by the use of a piezo crystal, for example, aquartz or a Rochelle salt crystal. The alternating current may beobtained in any conventional apparatus, such as a vacuum tubeoscillator, or a frequency multiplier, or a motordriven generator. Avariable frequency source may be employed if it is desired to vary thefrequency in accordance with the size of the objects being treated, orthe hardness or the mass of the metal or plastic being treated.

The vibration may be obtained by using pulsating D. 0. power, instead ofA. C. power. Thus for magnetic striction it is sufficient that themagnetic field build up and collapse at the desired frequency, thepolarization of the field being unimportant.

It will be understood that vibration may be produced in ways other thanthose specifically illustrated.

Spaced diaphragms may be used in a single tank without operating them inpush-pull. Thus multiple diaphragms may be disposed in a single wall,and all be operated in unison, or several spaced diaphragms may beoperated with a difference in phase, but without necessarily being inphase opposition.

Moreover, basically it is not even essential that there be a flexiblediaphragm in an otherwise rigid wall. In theory, the entire tank may bevibrated, or in contrast with that, a vibratile diaphragm with itsdriver may be suspended in the liquid, without touching or forming apart of the tank wall, in which case the tank wall need not be vibratedat all. However, it is believed that in every case it may be said thatthere is some form of mechanical network which is set into vibration asan entirety.

The elementary explanation that the dia-- phragm vibrates the liquid andthe objects in contact with each other may be too simplified. In anassembly of this sort, the volume and weight of the liquid and objectsusually go to form the mechanical equivalent of an impedance matchingnetwork which loads the entire system, keeping it in resonance with theexcitation frequency.

It will be understood that the article, objects and liquid arerelatively vibrated, and it is not essential that the vibration beinitially applied to the liquid per se to produce such relativevibration.

It is believed that the method of the present invention, as well as thenature of the apparatus which may be employed to practice the method,and the advantages thereof, will be apparent from the foregoin detaileddescription. It will also be apparent that while I have shown anddescribed my invention in several preferred forms,

changes may be made in the method and apparatus disclosed, withoutdeparting from the spirit of the invention as sought to be defined inthe following claims. In the claims the reference to placing a pluralityof objects in the liquid is intended to include a plurality of thearticles being treated, or one such article and a plurality of fillers,or a plurality of articles and a plurality of fillers. The reference toremoval of flash, fin, or burr is intended also to include the removalof the safety edge itself.

I claim:

1. The method of removing flash, fin, or burr from objects, whichincludes placing a plurality of objects in propinquity in a. liquid, andso vibrating said liquid at a relatively high frequency as to causemutual vibratory contact between said objects.

2. The method of removing flash, fin, or burr from objects, whichincludes placing a plurality of contacting and relatively movableobjects in a liquid, and vibrating said liquid at a sonic frequency inorder to cause mutual vibratory contact between said objects.

3. The method of removin flash, fin, or burr from objects, whichincludes placing a plurality of contacting and relatively movableobjects in a liquid, and vibrating said liquid at a supersonic frequencyin order to cause mutual vibratory contact between said objects.

4. Apparatus for removing flash, fin, or/and burr from objects, saidapparatus comprising a stationary container for a body of liquid, twospaced vibratile diaphragms contacting said liquid, means to vibrate oneof said diaphragms, and means to vibrate the other diaphragm at the samefrequency but with a difference in phase relative to the firstdiaphragm.

5. Apparatus for removing flash, fin, or/and burr from objects, saidapparatus comprising a a part of each of two oppositely disposed wallsof said container being a vibratile diaphragm,

means to vibrate one of said diaphragms, means to vibrate the otherdiaphragm at the same frequency but opposed phase relative to the firstdiaphragm.

6. Apparatus for removing flash, fin, or/and burr from objects, saidapparatus comprisinga stationary container fora body of liquid, meansfor supporting a plurality of objects in the body of liquid, the wallsof said container including two spaced vibratile diaphragms, means tovibrate one of said diaphragms, means to vibrate the other diaphragm atthe same frequency but opposed phase relative to the first diaphragm.

7. Apparatus for removing flash, fin, or/and burr from objects, saidapparatus comprising a stationary container for a body of liquid, meansfor supporting a plurality of objects in contact in the body of liquid,at least a part of each of two oppositely disposed walls of saidcontainer being a vibratile diaphragm, means to vibrate one of saiddiaphragms, means to vibrate the other diaphragm at the same frequencybut opposed phase relative to the first diaphragm, said diaphragms beingvibrated by said means at a fre- ,quency in the range of sonic andsupersonic frequencies.

8. Apparatus for removing flash, fin, or/and burr from objects, saidapparatus comprising a stationary container for a body of liquid, meansfor supporting a plurality of objects in propinquity in said body ofliquid, the walls of said container including two spaced vibratilediaphragms, means to vibrate one of said diaphragms, and means tovibrate the other diaphragm at the 6 same frequency, but with adifference in phase relative to the first diaphragm.

9. The method of removing flash, fin, or burr-from a molded article,which includes placing the article together with large filler objects inpropinquity in a liquid, and so relatively vibrating at high frequencythe article and liquid and filler objects as to cause mutual vibratorycontact between the article and the objects, said high frequency beingin the range of sonic and supersonic frequencies.

10. The method of removing flash, fin, or burr from molded objects,which includes placing a plurality of the molded objects in propinquityin a liquid, and so relatively vibrating said objects and liquid at highfrequency as to cause mutual vibratory contact between said objects,said high frequency being in the range of sonic and supersonicfrequencies.

HERBERT N. MAIER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 149,534 Smith Apr. 7, 18741,304,810 Sawyer May 27, 1919 2,402,967 Lubenow July 2, 1946 2,427,348Bond et al. Sept. 16, 1947 2,460,918 Bodine Feb. 8, 1949 2,468,550 Fruth1 Apr. 26, 1949 FOREIGN PATENTS Number Country Date 548,960 GreatBritain Oct. 30, 1942

